Well impact tools

ABSTRACT

A well tool for use with a jarring tool comprising an inner tubular member concentrically disposed in an outer cylindrical casing member, leaving an elongated annular chamber therebetween. Adaptors are provided at each end of the casing member for connection in a pipe string. An annular hammer member is mounted in the chamber for limited longitudinal movement therein.

States Patent [1 1 Roberts 4/1965 De Jamett ..l75/320 51 Apr.'3, 1973 2,953,351 9/1960 Bodine et al ..l75/293 X 1125,485 11/1963 Humphrey ..l75/320 X Primary Examiner-David H. Brown Attorney-Carlos A. Torres [57] ABSTRACT A well tool for use with a jarring; tool comprising an inner tubular member concentrically disposed in an outer cylindrical casing member, leaving an elongated annular chamber therebetween. Adaptors are provided at each end of the casing member for connection in a pipe string. An annular hammer member is mounted in the chamber for llimited longitudinal movement therein.

9 Claims, 5 Drawing Figures PATENTEUAPRS 1975 3 ,724,576

SHEET 2 UF 2 F163 F164 FIG. 5

Preston C. Roberts INVE N TOR ATTORNE Y WELL IMPACT TOOLS BACKGROUND OF THE INVENTION 1 Field of the Invention The present invention relates to well apparatus designed to impart high impact blows to well tools or other objects lodged in a well bore for the purpose of removing them. More specifically, the invention concerns apparatus for use with conventional jar devices so as to supplement or increase the force normally imparted by the jar.

2. Brief Description of the Prior Art In the drilling and production of oil and gas wells, tools or other objects occasionally become stuck in the well bore. It is then necessary to perform a fishing operation to remove the lodged item. A line of tools referred to as jar-s" has been developed to aid in such recovery. Usually the string of tools for removing such an item comprises, from the bottom upwardly, a spear or overshot, a bumper jar, a mechanical or hydraulic jarring mechanism, drill collars and the supporting pipe string. Usually, the first step in removal is to engage the lodged item with either the spear or overshot. After this is accomplished, tension is placed on the lodged item through the pipe string. The pull or tension on the pipe string causes the string to be elongated. The jarring mechanism is usually designed to allow tension to be placed on the string until a certain amount of elonga tion is reached. At this time the jarring mechanism is released and allows the elongated pipe to contract rapidly for a short distance, at which time it is suddenly stopped by the jar mechanism. The sudden halting of contraction by the jar imparts a high intensity blow against the lodged item, and it is hoped, causes the item to be unlodged for removal. The additional weight of the drill collars helps intensify the blow.

Of course, some items are more tightly lodged than others and sometimes are unresponsive to the blow of a conventional jar mechanism. The conventional jar mechanism inherently requires the release of tension on the lodged device. at the time the impact is imparted. There is reason to believe that a better effect could be obtained if the blow could be imparted while the object is held in tension. It would also be desirable to eliminate drill. collars if possible. The large outside diameter and length of drill collars makes for costly washing over in the event they become lodged while fishing. Furthermore, drill collars reduce theamount of tension that can beplacedonthe lodged objects, limitingthe magnitude of jarring impacts.

SUMMARY OF THE INVENTION The present invention provides a method whereby the impact produced by a jarring tool can be supplemented by a delayed impact applied after the lodged item is. jarred and placed again in tension. This is accomplished through a toolattached directly above the jarring mechanism. This multiplier tool, as it may be called, may comprise a cylindrical inner tube concentrically mountedin a cylindricalouter case to form an elongated annular cavityin which an annular piston or hammer member. is mounted for limited longitudinal movement. Suitable adaptors are provided at each end of the tool for attachment to the jar and the handling string. One oftheadaptors serves as an anvilfor the hammer member. The hammer member normally rests at the lower end of the annular cavity. When the jarring mechanism is tripped, causing the handling string to contract rapidly, the multiplier tool is rapidly accelerated in an upwardly direction. When the jarring mechanism has completed its free travel, it suddenly stops the contraction of the pipe string imparting a jarring blow to the lodged item and again placing it in tension. For a short time after the jar blow has been imparted, the multiplying tool hammer continues to move upwardly until it strikes the anvil within the chamber. Thus another high intensity blow is imparted to the lodged item immediately after the conventional jarring tool has delivered its blow and placed the lodged item in tension again. The combination of the blow from the jarring mechanism followed immediately by placing tension or pull 'on the lodged item while an additional high intensity blow is delivered will more likely result in dislodging recalcitrant objects. This also eliminates the need for drill collars. Other objects and advantages of the invention will be apparent from the description which follows.

BRIEF DESCRIPTION OF THE DRAWINGS In the following description, reference will be made to accompanying drawings in which:

FIG. 1 is a schematic representation of a multiplier tool in combination with a conventional jarring tool, according to a preferred embodiment of the invention, positioned in a well'bore to facilitate the release of a stuck drill;

FIG. 2 is a longitudinal cross-section of a multiplier tool, according to a preferred embodiment of the invention, shown in the rest position;

FIG. '3 is a longitudinal cross-section of a multiplier tool, according to another preferred embodiment of the invention, shown in its rest or neutral position;

FIG. 4 is a longitudinal cross-section of the embodiment of FIG. 3 shown in the position that would be assumed during free travel of a jarring tool to which it might be connected; and

FIG. Sis a longitudinal cross-section of the embodiments of FIGS. 3 and 4 showing the position assumed after free travel of an associated jarring tool, while imparting a blow for removing a lodged item in the well bore.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring first to FIG. 1 there is shown a well bore 10 in which a drill 12 has become lodgedby surrounding debris and material 14. After the free portion of the drill string has been removed, an overshot tool 16 is lowered into engagement with the: upper end of the stuck drill 12. Attached directlyabove overshot tool 16 is a bumper jar 18. Directly above the bumper jar 18 is a conventional mechanical or hydraulic jarring mechanism 20. Connected to the jarring tool 20 is a multiplier tool 22, a fulldescription of which will follow hereafter. A pipe string 24 is attached to the upper end thereon by placing tension on the pipe string 24, cans ing the string to be elongated to a predetermined limit. When this limit is reached, the jarring mechanism is released and allows the elongated string 24 to contract rapidly until it is stopped by the jar mechanism 20. The stopping of this contraction by the jar imparts a blow against the lodged item 12, and if the lodged item is not released, again places the string 24 in tension. As will be more fully understood hereafter, the multiplier tool 22 then imparts another blow to the lodged item 12 as it is under tension. In other words, the lodged item is struck by a blow from the jar and shortly thereafter while under tension is struck by another blow from the multiplier tool 22. A stubbornly lodged item is then much more likely to be released by such actions.

Referring now to FIG. 2, the multiplier tool 22 will be fully described. The tool may comprise a cylindrical outer casing 32 and a concentric inner tubular member 33 forming therebetween an annular chamber 35, in which is mounted an annular piston or hammer member 37. The casing 32 may be internally threaded at 46 and 47 for attachment to a lower adaptor 40 and an upper adaptor 42. The upper adaptor 42, which serves as an anvil also, may be threaded at 43 for attachment to a pipe string and the lower adaptor 40 may be threaded at 49 for attachment to a jarring tool. The inner tubular member 33 may be retained by annular shoulders 51 and 52 in counterbored portions of adaptors 42 and 40, respectively. O-ring seals 53, 54, 55 and 56 seal the chamber against the pressures within tube 33 and surrounding casing 32. The annular piston or hammer member 37 is shorter than the length of annular chamber 35. It will be noticed that this tool is a full opening tool allowing easy passage of wireline equipment and fluid.

As stated before, when utilized with a jarring tool, the multiplier tool 22 of the present invention imparts a delayed blow for application to a lodged item. This is accomplished in the following manner. When the elongated pipe string is released by the jar mechanism, it suddenly contracts until stopped by the jar at the time the jar imparts a blow to the lodged item. If the lodged item is not released 'by this blow, the string is then again placed under tension. Immediately after the jar mechanism is tripped, the pipe string moves upwardly at a high velocity, and consequently, the multiplying tool 22 does also. When the string comes to a stop, due to the jar, so does the multiplier tool 22, except for the hammer member 37. Since there is a space at the upper end of chamber 35, the hammer continues to travel upwardly until it strikes the adaptor or anvil 42, imparting a delayed blow to the lodged device.

Referring now to FIGS. 3 5, an alternate embodiment of the invention will be described. The multiplier tool 60 of this embodiment also comprises an outer case 62, an inner tube 64 and an annular chamber 66. It also comprises an upper adaptor or anvil 68 and a lower adaptor 70, threadingly attached to cylindrical case 62. Seals 71, 72, 73 and 74 seal the chamber 66 as in the previously discussed embodiment. Annular piston or hammer member 80 is also provided. However, in this embodiment, the inside and outside diameters of the lower end of hammer 80 are increased and decreased, respectively, to form a skirt portion 82, the cross-sectional annular area of which is, of course, less than the body portion of hammer 80. A corresponding lower portion of the chamber 66 is reduced in crosssection to form a short compression chamber 66a. An nular seals 85 and 86 are provided on the skirt 82 to sealingly and slidingly engage the inner and outer walls of the compression section 66a. The chamber 66 is precharged with a compressible fluid, such as nitrogen. A longitudinal groove 87 may be provided in the body portion of hammer for pressure equalization at each end of chamber 66. However, since the seals 85 and 86 on the skirt 82 sealingly engage the walls of the short compression section 660, the weight of hammer 80 will compress fluid in compression section 66a until the pressure is high enough to hold the hammer 80 in the neutral position of FIG. 3.

The multiplier tool of FIGS. 3 5 is employed in the same manner as the previously discussed embodiment. When the jarring tool, used with the multiplier tool, is released, there is a sudden and rapid upward acceleration of the pipe string and the multiplier tool 60. This sudden acceleration, while the jar mechanism is in its free travel, causes the hammer 80 to further compress fluid in compression section 66a until it assumes the approximate position of FIG. 4, near the end of jar mechanism free travel. After the jar free travel, a blow is delivered to the lodged item through the jar mechanism. The movements of all components of the multiplier tool 60, except for hammer 80, are arrested at this time. The inertia of hammer 80 and the gas compressed in compression section 66a will cause the hammer 80 to continue traveling upwardly until it delivers a high intensity blow to anvil 68 in the position of FIG. 5. Thus another high intensity blow'is imparted to the lodged item in the well bore at some delayed period of time.

With the present invention, a high intensity blow may be imparted to a lodged item immediately after a conventional jarring mechanism has delivered a previous blow and placed tension or pull back on the. lodged item. The combination of the blow by the jarring mechanism followed immediately by placing tension on the lodged item while an additional high intensity blow is delivered, is extremely effective for removing stubbornly lodged items from a well bore. Although only two embodiments of the invention have been described herein, many other variations will be obvious to those skilled in the art and the scope of the invention is intended to be limited only by the claims which follow.

I claim:

1. A well tool comprising a tubular member concentrically disposed in a cylindrical casing member to form an annular chamber therebetween, first and second adaptors at each end of said members adapted for connecting said well too] in a pipe string, and an' annular piston like hammer member mounted for limited longitudinal movement within said chamber, one end'of said annular chamber being reduced in cross-sectional- 4, A well tool as set forth inclaim 4, characterized in that said one end of said hammer member is of a crosssectional area less than the opposite end of said hammer member.

5. A well tool as set forth in claim 4, characterized in that said hammer member is provided with a longitudinal passage providing fluid communication between said one end and said opposite end.

6. In combination with a jarring tool and connected therewith in a pipe string, a well tool comprising a flow tube concentrically disposed in a cylindrical casing leaving an annular chamber therebetween, said flow tube and casing being connected at each end to adaptor means for connection in said pipe string, an annular piston like hammer disposed in said chamber for limited longitudinal movement therein, one end of said hammer being adapted to strike an anvil portion of said adaptor means at one end of said chamber to impart a delayed blow to a lodged object in a well bore after said jarring tool has imparted a previous blow to said lodged item.

7. In combination, a jarring tool and well tool as set forth in claim 6, characterized in that said chamber is charged with a compressible fluid at one end of said hammer on relatively rapid longitudinal movement of said tube and casing in one direction, to deliver a high intensity blow to said anvil through said hammer on the arresting of said longitudinal movement.

8. In combination, a jarring tool and well toolas set forth in claim 7, characterized in that the cross-sectional area at said one end of said chamber is reduced to provide surfaces for engagement with a tubular skirt at said one end of said hammer, said skirt sealingly engaging said compression section during said movement of said tube and casing and being adapted to disengage said compression section on the arrest of said move- 

1. A well tool comprising a tubular member concentrically disposed in a cylindrical casing member to form an annular chamber therebetween, first and second adaptors at each end of said members adapted for connecting said well tool in a pipe string, and an annular piston like hammer member mounted for limited longitudinal movement within said chamber, one end of said annular chamber being reduced in cross-sectional area to provide a compression section engageable with one end of said hammer member.
 2. The well tool of claim 1, characterized in that said annular chamber is isolated by seal means from the pressure environment on the interior of said tubular member and the exterior of said casing.
 3. A well tool as set forth in claim 1, characterized in that said chamber is charged with a compressible fluid.
 4. A well tool as set forth in claim 4, characterized in that said one end of said hammer member is of a cross-sectional area less than the opposite end of said hammer member.
 5. A well tool as set forth in claim 4, characterized in that said hammer member is provided with a longitudinal passage providing fluid communication between said one end and said opposite end.
 6. In combination with a jarring tool and connected therewith in a pipe string, a well tool comprising a flow tube concentrically disposed in a cylindrical casing leaving an annular chamber therebetween, said flow tube and casing being connected at each end to adaptor means for connection in said pipe string, an annular piston like hammer disposed in said chamber for limited longitudinal movement therein, one end of said hammer being adapted to strike an anvil portion of said adaptor means at one end of said chamber to impart a delayed blow to a lodged object in a well bore after said jarring tool has imparted a previous blow to said lodged item.
 7. In combination, a jarring tool and well tool as set forth in claim 6, characterized in that said chamber is charged with a compressible fluid at one end of said hammer on relatively rapid longitudinal movement of said tube and casing in one direction, to deliver a high intensity blow to said anvil through said hammer on the arresting of said longitudinal movement.
 8. In combination, a jarring tool and well tool as set forth in claim 7, characterized in that the cross-sectional area at said one end of said chamber is reduced to provide surfaces for engagement with a tubular skirt at said one end of said hammer, said skirt sealingly engaging said compression section during said movement of said tube and casing and being adapted to disengage said compression section on the arrest of said movement, permitting said hammer to strike said anvil portion.
 9. In combinAtion, the jarring tool and well tool of claim 8 characterized in that said hammer comprises an annular passageway providing fluid communication between the anvil end of said chamber and the area of said chamber surrounding said hammer at the point of connection with said skirt member. 